tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
I was wondering how to best implement builtin function calls, but I don't think
actually generating bytecode for them makes much sense.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D134958
Files:
clang/lib/AST/CMakeLists.txt
clang/lib/AST/Interp/ByteCodeExprGen.cpp
clang/lib/AST/Interp/Interp.h
clang/lib/AST/Interp/InterpBuiltin.cpp
clang/lib/AST/Interp/Opcodes.td
clang/test/AST/Interp/builtins.cpp
Index: clang/test/AST/Interp/builtins.cpp
===================================================================
--- /dev/null
+++ clang/test/AST/Interp/builtins.cpp
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -verify %s
+// RUN: %clang_cc1 -verify=ref %s
+
+// expected-no-diagnostics
+// ref-no-diagnostics
+
+
+static_assert(__builtin_clz(10) == 28, "");
Index: clang/lib/AST/Interp/Opcodes.td
===================================================================
--- clang/lib/AST/Interp/Opcodes.td
+++ clang/lib/AST/Interp/Opcodes.td
@@ -169,6 +169,13 @@
let HasCustomEval = 1;
}
+/// Call a builtin function.
+def CallBI : Opcode {
+ let Args = [ArgUint32];
+ let Types = [];
+ let ChangesPC = 1;
+}
+
//===----------------------------------------------------------------------===//
// Frame management
//===----------------------------------------------------------------------===//
Index: clang/lib/AST/Interp/InterpBuiltin.cpp
===================================================================
--- /dev/null
+++ clang/lib/AST/Interp/InterpBuiltin.cpp
@@ -0,0 +1,23 @@
+//===----- InterpBuiltin.cpp - Interpret builtin functions ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Integral.h"
+#include "InterpState.h"
+
+namespace clang {
+namespace interp {
+
+bool InterpretBuiltinClz(InterpState &S) {
+ auto Arg = S.Stk.pop<Integral<32, false>>();
+ auto Result = Arg.countLeadingZeros();
+ S.Stk.push<Integral<32, true>>(Integral<32, true>::from(Result));
+ return true;
+}
+
+} // namespace interp
+} // namespace clang
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -25,6 +25,7 @@
#include "clang/AST/ASTDiagnostic.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/Expr.h"
+#include "clang/Basic/TargetBuiltins.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/Support/Endian.h"
@@ -91,6 +92,10 @@
/// Checks if a method is pure virtual.
bool CheckPure(InterpState &S, CodePtr OpPC, const CXXMethodDecl *MD);
+/// Prototypes for evaluation of builtin functions.
+/// Implemented in InterpBuiltin.cpp
+bool InterpretBuiltinClz(InterpState &S);
+
template <typename T> inline bool IsTrue(const T &V) { return !V.isZero(); }
//===----------------------------------------------------------------------===//
@@ -1090,6 +1095,16 @@
return true;
}
+inline bool CallBI(InterpState &S, CodePtr OpPC, uint32_t ID) {
+ switch (ID) {
+ case Builtin::BI__builtin_clz:
+ return InterpretBuiltinClz(S);
+
+ default:
+ return false;
+ }
+}
+
//===----------------------------------------------------------------------===//
// Read opcode arguments
//===----------------------------------------------------------------------===//
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -943,42 +943,56 @@
template <class Emitter>
bool ByteCodeExprGen<Emitter>::VisitCallExpr(const CallExpr *E) {
- assert(!E->getBuiltinCallee() && "Builtin functions aren't supported yet");
-
const Decl *Callee = E->getCalleeDecl();
if (const auto *FuncDecl = dyn_cast_or_null<FunctionDecl>(Callee)) {
- const Function *Func = getFunction(FuncDecl);
- if (!Func)
- return false;
- // If the function is being compiled right now, this is a recursive call.
- // In that case, the function can't be valid yet, even though it will be
- // later.
- // If the function is already fully compiled but not constexpr, it was
- // found to be faulty earlier on, so bail out.
- if (Func->isFullyCompiled() && !Func->isConstexpr())
- return false;
-
+ unsigned BuiltinID = E->getBuiltinCallee();
QualType ReturnType = E->getCallReturnType(Ctx.getASTContext());
Optional<PrimType> T = classify(ReturnType);
- // Put arguments on the stack.
- for (const auto *Arg : E->arguments()) {
- if (!this->visit(Arg))
+
+ if (BuiltinID != 0) {
+ assert(*T);
+ FuncDecl->dump();
+
+ // Put arguments on the stack.
+ for (const auto *Arg : E->arguments()) {
+ if (!this->visit(Arg))
+ return false;
+ }
+ return this->emitCallBI(BuiltinID, E);
+
+ } else {
+ const Function *Func = getFunction(FuncDecl);
+
+ if (!Func)
+ return false;
+ // If the function is being compiled right now, this is a recursive call.
+ // In that case, the function can't be valid yet, even though it will be
+ // later.
+ // If the function is already fully compiled but not constexpr, it was
+ // found to be faulty earlier on, so bail out.
+ if (Func->isFullyCompiled() && !Func->isConstexpr())
return false;
- }
- // Primitive return value, just call it.
- if (T)
- return this->emitCall(*T, Func, E);
+ // Put arguments on the stack.
+ for (const auto *Arg : E->arguments()) {
+ if (!this->visit(Arg))
+ return false;
+ }
- // Void Return value, easy.
- if (ReturnType->isVoidType())
- return this->emitCallVoid(Func, E);
+ // Primitive return value, just call it.
+ if (T)
+ return this->emitCall(*T, Func, E);
- // Non-primitive return value with Return Value Optimization,
- // we already have a pointer on the stack to write the result into.
- // TODO: Is this always the case?
- if (Func->hasRVO())
- return this->emitCallVoid(Func, E);
+ // Void Return value, easy.
+ if (ReturnType->isVoidType())
+ return this->emitCallVoid(Func, E);
+
+ // Non-primitive return value with Return Value Optimization,
+ // we already have a pointer on the stack to write the result into.
+ // TODO: Is this always the case?
+ if (Func->hasRVO())
+ return this->emitCallVoid(Func, E);
+ }
} else {
assert(false && "We don't support non-FunctionDecl callees right now.");
}
Index: clang/lib/AST/CMakeLists.txt
===================================================================
--- clang/lib/AST/CMakeLists.txt
+++ clang/lib/AST/CMakeLists.txt
@@ -73,6 +73,7 @@
Interp/Frame.cpp
Interp/Function.cpp
Interp/Interp.cpp
+ Interp/InterpBuiltin.cpp
Interp/InterpBlock.cpp
Interp/InterpFrame.cpp
Interp/InterpStack.cpp
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